The invention concerns a process and a device for dewatering a fiber web, especially paper web, using vacuum.
In known processes, dewatering of, e.g., a paper web on an air-permeable wire or felt takes place after the forming zone with vacuum that extracts water from the web and the wire or felt through boxes located under the web and the wire. Vacuum dewatering is used particularly in tissue machines working according to the through drying principle. The water is normally extracted through slots in a plate over which the paper web passes. The goal of the dewatering is to achieve as high a dryness of the paper web as possible after application of the vacuum. However, the achievable dryness is limited by the intensity of the vacuum and the slot width.